ICAO does not, as far as I know, specify Category A peformance to the detail that the FAA or CAA or JAA would do it. ICAO says you have to set out criteria, and the FAA/CAA/JAA then sets out their own criteria.
If you want to know the criteria for the FAA, then look in Part 29 of 14CFR (the politically correct term for what we all in aviation know as the FARs). to get an idea of what paragraphs apply, look at Appendix D of Part 27, which lists all the appropriate paragraphs of Part 29 for Category A. There are quite a few, and most are based on performance following an engine failure. There are a few that deal with other redundancy issues.
There shouldn't be much difference between the FARs and JARs when it comes to Category A performance, but I haven't done a side-by-side comparison.